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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
At 603 K, Kc for the reaction NH4Cl <===> NH3 + HCl is 0.011. What is the equilibrium concentration of NH3 if the initial concentration of NH4Cl is 0.500 M. Please help me with this question because i got 2 answers so prove me.

Chemistry
How many grams of NaN₃ must be decomposed to fill a 42.0 L airbag with nitrogen gas at a pressure of 1.05 atm and a temp of 29.5 degrees Celsius?

Chemistry
What substance is acting as the Brønsted-Lowry base in the forward reaction below? H2O + NH3 yields NH4+ + OH-

Chemistry, Heat and Phase changes(general chem II)
From the data below, calculate the total heat (in J) needed to convert 22.00 g of icea t -6.00 C to liquid water at 0.500 C. melting point at 1 atm: 0.0 C Hfusion: 6.02 KJ/mol cliquid: 4.21 J/g C csolid: 2.09 J / g C My answer is about 300 J short of the correct answer. It ...

Chemistry
Hello I need help with this excersise: How many moles of NH4Cl are neccesary to add to 1 liter of solution of Co2+ 0,20 M in order to prevent the precipitation when the solution is saturated with H2S (0,1M) and the pH is 7,50. It 's known that pKbNH3=4,75 ; Kps(CoS)=2,0×10^-...

Organic Chemistry
Would a C-Cl bond be polar or nonpolar in a molecule if both have a formal charge of 0? I thought at first that it would be polar just due to their electronegativities (just by looking at the periodic table), but if they both have a formal charge of 0, does that make it a ...

Chemistry
The homework question said "which 2nd row element has 6 valence electrons and a valence of 2?" I don't really understand the question, because oxygen would be the element with the 6 valence electrons, but wouldn't that mean that it has a valence of 6? Does the "valence of 2" ...

CHEMISTRY
CALCULATE THE DECREASE IN TEMPERATURE FOR 22.0 G SILVER THAT LOSES 625 J

Chemistry
How much 3M HCL will be used in order to prepare 250ml of 1M HCL

chemistry
How to determine saturation point of k2Cr2O7?

Chemistry
Mg + HCl -------> MgCl2 + H2 What volume of HCl is required from 27 % HCl to form 12.1 gram H2? ( D = 1.41 g/ml)

Chemistry
how many joules of energy are needed to change 400 grams of water from 35 degrees C to 45 degrees C?

Chemistry
Calculate the volume of 1.0 M CuSO4 stock solution you should use to make 100 mL of a 0.010 m CuSO4 solution.

Chemistry
How do I calculate the amounts of Na2SO4 and CaCl2 that I need to create a solution of CaSO4 at 9 grams/Liter concentration?

Chemistry
How many electrons in CH3NH3+ ?

Chemistry
Which is a conjugate pair in the following equilibrium? H2C2O4(aq) + HPO4(aq) 2- HC2O4(aq)- + H2PO4(aq)-

biology
which of the following is consistent with the theory of vitalism ? A.all matter contains a vital force** b.the chemistry of life and nonlife are similar c. living things contain a vital force absent in nonliving things d. life must be sustsained through a series of chemical ...

biochemistry
which of the following is consistent with the theory of vitalism ? A.all matter contains a vital force** b.the chemistry of life and nonlife are similar c. living things contain a vital force absent in nonliving things d. life must be sustsained through a series of chemical ...

chemistry
From a laboratory process designed to separate water into hydrogen and oxygen gas, a student collected 10.2 g of hydrogen and 66.9 g of oxygen. How much water was originally involved in the process?

Chemistry(please check my answer)
Which of the following is an oxidation reaction? A. AuCl4- → AuCl 2- **** B. Mn7+ → Mn2+ C. Cl2 → ClO3- D. Co3+ → Co2+

Chemistry(please check my answer)
Among the following, which is an oxidation-reduction reaction? A. Na2S + CaCO3 → CaS + Na2CO3 B. 2HNO3 + Mg(OH)2 → Mg(NO3)2 + 2H2O C. H2 + F2 → 2HF**** D. 3Ba(OH)2 + 2H3PO4 → Ba3(PO4)2 + 6H2O

Chemistry(please check my answer)
When the equation HCl + MnO2 → MnCl2 + H2O + Cl2 is balanced, what is the coefficient for HCl? A. 1 B. 2 C. 3 D. 4***

Chemistry (please check my answer)
Identify a false statement about how to protect iron from corrosion. A. Coat the surface with oil, paint, or plastic. B. Attach a metal that is more easily reduced. ******* C. Exclude air and water. D. Attach a metal that is a better reducing agent.

intergrated rate law chemistry
The decomposition of ammonia on a platinum surface at 1129 K occurs according to the following reaction: 2NH3 (g) ¨ N2(g) + 3H2(g). Use the following kinetic data which report the variation of ammonia concentration in the gas phase with time to evaluate the order of ...

chemistry
12M HCl + H20→ 5M HCl How much water? Total Volume= Pls I need this tomorrow

Chemistry
Which of the following is true concerning the reaction below? H2S + HNO3 → S + NO + H2O A. S is reduced. B. H is oxidized. C. N is reduced. D. O is oxidized. ***

chemistry
it was found that in an experiment tthat a gas c diffuses 8.76¡Á10^-1 times faster than nitrogen gas calculate the molecular mass of gas c (n=14)

Chemistry
When 38.21 g of pure copper reacts with 192.83g of iodine, 190.83g of a compound containing only copper and iodine result. 40.21g of iodine remain when the reaction is complete. a. Do these results support the Law of Conservation of Mass? Explain. b.does this compund obey the ...

Chemistry
Oxy acetylene welding uses acetylene gas which is produced by the reaction of CaC2 with water. It also produces calcium hydroxide as a by product.Calculate the volume in liters measured at 27°C and 965 torr that would be produced from the complete reaction of 11.2 g of CaC2 ...

Chemistry
If a 29.9 g sample of the liquid cyclohexane has a volume of 38.6 mL, what is the specific gravity of the compound? Take the density of water to be 1.00 g/mL.

Chemistry
A Helium Gas Ballon Has A Volume Of 12.0L. At Room Temperature(25 Degrees Celcius) The Internal Pressure Is .05ATM. Calculate The Number Of Moles Of Helium In The Balloon?

Science, chemistry
During the experiment, 100ml will be required to prepare 0.5M solution of NaNO3. Calculate the mass of NaNO3 in grams that will be required.

chemistry
Answer the following questions about Fe(NO3)3. a. What is the mass percent of iron in this compound? b. A different iron compound is 34.43% by mass iron. What mass of this compound is needed to get 125g of pure iron?

Chemistry
A 100.00g sample of the gaseous hydrocarbon ethane is a gaseous hydrocarbon, with 79.89g of carbon and 20.11g of hydrogen. Ethylene is a different gas phase hydrocarbon. A 100.00g sample of ethylene has 85.63g of carbon with 14.37 of hydrogen. A sample of a hydrocarbon has 64....

Chemistry
At normal temperature and pressure, air has a density of 0.001184 g/mL. What is the mass of air in a room that is 3.93 m by 2.28 m by 2.25 m?

Chemistry
A solution is 40% acetic acid by mass. The density of this solution is 1.049 g/mL. Calculate the mass of pure acetic acid in 460 mL of this solution at 20 C. Answer in units of g.

Chemistry
I have no idea how to solve this problem could someone explain it to me please What will be the approximate volume when the temperature is 900 kelvin?

chemistry
What is the solubility of BaSO4 in a solution of 0.250 M Na2 SO4 ? The Ksp of BaSO4 is 8.7 x 10-11.

Chemistry
A salt water swimming pool is 47.0 m long, 25.1m wide, and 2.79 m deep. If the pool is filled with salt water having a density of 1.06 g/ cm3, how many pounds of salt water are in the pool when it is filled? 1 kg = 2.20 lb I'm not sure how to approach this. I've tried ...

chemistry
C2O4-- + I- + H+ ---> I2+CO2+H2O

Organic Chemistry
The pKa of CH3COOH is 4.76. What statement describes a solution of CH3COOH at pH of 6.4?

Chemistry
7. A 100.00g sample of the gaseous hydrocarbon ethane is a gaseous hydrocarbon, with 79.89g of carbon and 20.11g of hydrogen. Ethylene is a different gas phase hydrocarbon. A 100.00g sample of ethylene has 85.63g of carbon with 14.37 of hydrogen. A sample of a hydrocarbon has ...

Bio physics chemistry pre medical
Methane react with steam to form h2 and co. . what volume of h2 can be obtained from 100cmcube of methane at the standard temperature and pressure? ?

Bio physics chemistry pre medical
The vitamin a has a molecular formula c 20 h 30 o. How much no of molecules will be vitamin a has in 500mg capsule?

Bio physics chemistry pre medical
Vitamin a has a molecular formula c 20 h 30 o. How much no of molecules will vitamin a contian in 500mg capsule? ? Plz tell me now tomorrow is my test .I will be very grateful of u. .

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...

Chemistry
How many potassium ions are present in the following: 1) 3 moles of potassium chloride.

Bio physics chemistry pre medical
Vitamin a has a molecular formula c 20 h 30 o. How much no of molecules will vitamin a contian in 500mg capsule? ? Plz tell me now tomorrow is my test .I will be very grateful of u. .

Bio physics chemistry pre medical
Methane react with steam to form h2 and co. . what volume of h2 can be obtained from 100cmcube of methane at the standard temperature and pressure? ?

Chemistry
if 12.8g of NaCl is added to 243.2 mL of water (density (1.00g/mL)). the volume occupied by the solution is 250.0 mL. Calculate the density of the salt water.

Chemistry
The weight of kclo3 which thermal decomposition o2 gas sufficient for the combustion of 1.12 litres of ethlene gas at STPis

Chemistry
One volume of a hydrocarbon require 3 volume of oxygen for complete combustion then formula for hydrocarbon

Chemistry
How many electrons involved in the reduction of one mole of Al2o3 to aluminium metal

Chemistry
How many moles of potassium permanganate is necessary to oxidise o.5 moles of soadium sulphate in acid medium

Chemistry
A flask of known volume was filled with air to a pressure of 3.6atm. This flask was then attached to an evacuated flask of known volume and the air was allowed to expand into the flask. The final pressure of the air (in both flasks) was 2.7atm and the volume of the second ...

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...

Chemistry
Hello, please I need help with this excersice of chemical equilibrum. I really don't get what "1:6" means and how can I use that proportion". The excercise says: "0,014" moles of HCl are dissolved in water in a proportion of 1:6 (1 mole of HCl per 6 moles of H2O). What is the ...

Chemistry
Why is the heat of neutralization between HCL and NaOH is higher than CH3COOH and NaOH

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...

chemistry
how to differenciate potassium carbonate from calcium carbonate in terms of deliquiscence,hygroscopy and efflorescence

chemistry
how to differenciate potassium carbonate from calcium carbonate in terms of deliquiscence,hygroscopy and efflorescence

Chemistry
How Many Atoms Are There In 10grams Of Carbon

Chemistry
How Many Atoms Are There In 10grams Of Carbon And How Many Molecules Are There In 10grams Of Calcium Carbonate

chemistry
A solution is made by mixing 25 mL of .35 M LiOH with 15.5 mL of .2225 M NH3. Kb=1.8x10^-5 for NH3 Calculate the pH for the solution.

chemistry
2.2. Billions of kilograms of urea, are produced annually for use as a fertilizer. The reaction used is given below. NH3(g) + CO2(g) → CO(NH2)2(s) + H2O(l) The typical starting reaction mixture has a 3:1 mole ratio of NH3 to CO2. If 47.7 g urea forms per mole of that ...

Chemistry
Which of the following would be the best to measure 18mL of acohol accurately and precisely

Chemistry
One hundred grams of mixture of NaSO4 – 10H2O and Na2CO3 – 10H2O are heated to drive off water of hydration. The final weight of the mixed salts is 39.6g. What is the ration of moles Na2CO3 to moles Na2SO4 in the original hydrated salts?

Chemistry
25.0 mL of an H3BO3 solution were titrated with 29.15 mL of a 0.205 M LiOH solution to reach the equivalence point. what is the molarity of the H3BO3 solution?

chemistry
how much NAOH must be added to 500ml acetic acid 0.5Mol to give ph 0.5

Chemistry
A 2.80-g sample of haematite ore containing Fe3+ ions was dissolved in a concentrated acid and the solution was diluted to 250 mL. A 25.0 mL aliquot was reduced with Sn2+ to form a solution of Fe2+ ions. This solution of Fe2+ ions required26.4mL of a 0.0200 M K2Cr2O7 solution ...

chemistry
how to balance combustion of 5% by volume in air. 1. 0.05 CH4 + ( )(0.21 O2 + 0.79 N2) 2. ( )CH4 + O2 + 0.376 N2

Chemistry
How many moles of chloride ions are in 0.04dm^3 of 0.45M calcium chloride CaCl2

Chemistry
What mass of glucose (c6h12o6)is produced from 18g of co2 when it reacts with water molecule? 6Co2+6H2o→c6h12o6+Co2

Chemistry
What is the mole fraction of ethanol, C2H5OH, in an aqueous solution that is 50.0% ethanol by mass?

chemistry
which of following show cistrans isomerism?

chemistry
The amount of sulphuric acid (in gm) required to neutralise 10L of ammonia at STP is

Chemistry
There are three naturally occurring isotopes of the hypothetical element hilarium 41Hi, 42Hi, and 44Hi. The percentages of these isotopes are the following: Hilarium Natural Isotopes Abundance 41Hi 18.7% 42Hi 43.6% 44Hi 37.7% You can assume that the atomic masses are exactly ...

chemistry
When 25 mL of C2H5OH (density 0.80 g.cm-3) is dissolved in water to prepare a 250 mL solution, the density of the solution was found to be 0.950 g.cm-3. Calculate a. Molarity of pure ethanol; b. Molarity of ethanol in the final solution; c. Volume of the final solution which ...

chemistry
What is the equilibrium expression for the following acid dissociation reaction? CH3COOH + H2O CH3COO- + H3O+ A. [CH3COO-][H3O+]/[CH3COOH][H3O] B. [CH3COOH][H2O]/[CH3COO-][H3O+] C. [CH3COOH]/[CH3COO-][H3O-] D. [CH3COO-][H3O+]/[CH3COOH]

chemistry
A reaction has an equilibrium constant very much less than 1. Will the reaction proceed spontaneously? A. Yes, because products are favored and deltaG° < 0. B. Yes, because reactants are favored and deltaG° > 0. C. No, because reactants are favored and deltaG° > 0...

chemistry
If the equilibrium constant is much less than 1, how can you tell where the equilibrium lies? A. Reactants are in the numerator of the equilibrium expression, so equilibrium lies toward the reactants. B. Products are in the numerator of the equilibrium expression, so ...

chemistry
What information does an equilibrium constant give about a reaction? A. It tells how long it takes the reaction to reach equilibrium. B. It tells how much energy is required for the reaction to happen. C. It tells what the rate constant of the reaction is at equilibrium. D. It...

Chemistry
determine the ph of 5 grams KNO3 that is dissolved in 100ml water.KNO3 is produced by mixing .2M KOH and 0.2M HNO3...please help me...pls..

Chemistry
determine the ph of 5 grams KNO3 that is dissolved in 100ml water.KNO3 is produced by mixing .2M KOH and 0.2M HNO3...please help me...

chemistry
A piece of zinc was added to 1000cm³ of 0.2m hydrochloric acid. After effervescence head stopped, 30cm³ of the resulting solution required 22cm³ of 0.08m sodium trioxocarbonate (iv) solution for complete neutralization, calculate the mass of zinc added.

chemistry
P4 + HNO3 = H3PO4 + NO2 + H20 by partial method balancing

chemistry
If your favorite silver jewelry ever tarnishes and you happen to have some aluminum foil on hand, you can actually get rid of some of that tarnish. The tarnish here is actually silver sulfide. If you put the jewelry and aluminum into a dish with enough water to cover them both...

Science Chemistry
Calculate the no. of grams of NaOH req. to absorb volume of the CO2 gas produce as Na2CO3

chemistry
how many moles of fe are present in 30g of rust?

Chemistry
How many grams of KCl should be added to 1.5kg of water to lower its freezing point to -7.5°C

chemistry
When is there a need to determine G? A. When H > 0 and S < 0 B. When H > 0 and S = 0 C. When H > 0 and S > 0 D. When H = 0 and S < 0

science - chemistry
How can we separate a mixture of iodine, napthalene, chalk dust and saw dust. Write the ans in the form of a flow chart.

chemistry
what is the concentration of na and co3 ions in 0.2M aqueous solution of na2co3

chemistry help!!! please!!! DrBob222 I need you!!
How many atoms of carbon are needed to produce 0.45 mol Al? 3C + 2Al2O3 4Al + 3CO2 A. 2.6 × 1026 atoms B. 9.7 × 1024 atoms C. 3.0 × 1022 atoms D. 2.0 × 1023 atoms I'm really very stuck with this question. please help me!!!

chemistry help!!! please!!! DrBob222 I need you!!
The G value for formation of gaseous water at 298 K and 1 atm is -278 kJ/mol. What is the nature of the spontaneity of formation of gaseous water at these conditions? A. The reaction is sometimes spontaneous. B. The reaction is spontaneous. C. The reaction may or may not be ...

CHEMISTRY
Why is glass considered as a supercooled liquid? answer please!!!

chemistry
The reaction CHCL3(g)+CL2(g)_CCL4(g)+HCL(g) has the following rate law:Rate =k [CHCL3][CL2].If the concentration of CHCL3 is increased by a factor of five while the concentration of CL2 Is kept the same use a mathematical equation to show the factor by which the rate will ...

CHEMISTRY
why is glass called a supercooled liquid?

chemistry
How many atoms of carbon are needed to produce 0.45 mol Al? 3C + 2Al2O3 4Al + 3CO2 A. 2.6 × 1026 atoms B. 9.7 × 1024 atoms C. 3.0 × 1022 atoms D. 2.0 × 1023 atoms

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